1. Field of the Invention
The present invention relates to a sealing slide fastener, and more particularly to a fluid-tight sealing slide fastener having means for providing a sealing capability between a top stop and a slider against the leakage of air and water when the slide fastener is closed.
2. Prior Art
Various slide fasteners have been devised and put to use for providing a fluid-tight sealing capability against the leakage of air and water through the closed slit between adjacent edges. However, the prior fluid-tight slide fasteners have failed to give a sufficient sealing ability between a top stop and a slider when the slide fastener is closed.
Japanese Patent Publication No. 33-5328 published on July 23, 1958 discloses a fluid-tight sealing slide fastener. The disclosed slide fastener has a top stop made of an elastomeric material such as rubber and including a U-shaped body opening toward the bottom stop. The top stop has ridges on an upper surface thereof. When the slide fastener is closed by the slider, the slider is positioned on the top stop with the ridges thereon being compressed by an upper plate of the slider for rendering the top stop fluid-tight against the passage of air and water.
However, the known sealing slide fastener suffers various shortcomings. For example, the ridges on the top stop tend to wear due to abrasive engagement with the upper plate of the slider while the slider is repeatedly moved to open and close the slide fastener. The worn ridges cannot provide a sufficient fluid-tight sealing ability. The movement of the slider as it engages the top stop is relatively sluggish since the ridges on the top stop are resiliently pressed against the upper plate of the slider. An additional problem is that since the slider has no positive stop, the slider on the closed slide fastener is likely to slip off the top stop under a relatively strong force imposed on the slider, frequently allowing the slide fastener to be opened undesirably.